Is it better to downshift when driving a standard?

I drive a standard 91 Toyota Pickup and have different advice on whether or not to downshift. Some people have told me it does not really matter and you can simply shift into neutral and coast to a stomp to lay off your clutch. However, I have also been told down shifting is better for your transmission. But, the only explanation i have been able to get as to why this is so is the vague explanation that it is good to cycle to gears backwards. But i do not understand why. Can anyone explain all of this to me, i LOVE this truck and want it to last forever.